The invention relates to agricultural seeders, such as hoe openers and seeding tools used in farming operations to distribute seeds into the soil.
Generally, precision hoe openers are mounted to the frame of an implement which is towed behind a tractor. These openers may include a ground engaging tool or ground opener that opens the soil, providing a seeding path for seed deposition into the soil. The ground opener is used to break the soil to enable seed deposition. After the seed is deposited, the ground engaging tool may be followed by a packer wheel that packs the soil on top of the deposited seed. The packer wheel may be rigidly mounted behind the ground engaging tool via a structural member or rear frame. Thus, the ground engaging tool and packer wheel generally move together with the same upward and downward motion. This vertical motion, somewhat independent of the implement frame, allows for more precise placement of seed in the soil.
Unfortunately, existing precision hoe openers do not adequately address the need for height variation over terrain during seeding, or for transportation when not seeding. It is generally undesirable to pull the hoe opener through soil when merely transporting the opener from one location to another. In addition, during seeding, existing openers do not provide adequate vertical motion of the opener and related assembly without compromising the load on the ground engaging tool and packer wheel. As a result, variations in the terrain can result in drastic changes in the packing force (e.g., normal force) of the packer wheel on the terrain being seeded by the opener and, also, the draft force of the terrain on the ground engaging tool. In turn, this variation in packing and ground opening force can result in non-uniform seeding depths and packing density in the terrain being seeded by the system.
The distance between the packer wheel and ground engaging tool can also affect the seeding accuracy of the opener assembly. Existing precision hoe openers have a fixed distance between the packer wheel and opener. A greater distance between the components will cause variations in the terrain to greater affect the force on the ground engaging tool or packer wheel. This will also result in non-uniform force applied to the soil by the two components, which reduces seeding accuracy. For instance, some existing precision hoe openers may employ a parallel linkage to control the location of the packer wheel and opener. One of the difficulties in using a parallel linkage is that the force at the packer wheel will fluctuate as the draft force applied to the opener displaces the linkage.
Existing precision hoe openers also require substantial force to raise the opener assembly, including the ground engaging assembly and packer wheel. This requirement results in the use of large hydraulic cylinders to raise the apparatus, due to the overall length and weight of each opener assembly. This hydraulic equipment is costly and takes resources (i.e. hydraulic power) from other portions of the tractor and seeding implement.
There is a need, therefore, for improved arrangements in precision hoe openers and seeder systems that improve the accuracy of the seeding operation. There is a particular need for a precision hoe opener configuration that applies forces to the ground engaging tool and the packing wheel to improve seeding accuracy while also increasing the mobility of the opener.